A Slidell woman told a St. Tammany Parish court on Tuesday that she watched her boyfriend beat their 5-month-old son and did nothing to stop him out of fear. She didn't want to get hurt, she told the court.

Andrea Renae Polizzi, 20, pleaded guilty to second-degree cruelty to juveniles. Judge Allison Penzato sentenced her to 20 years in prison, suspended 10, and added five years of probation. The baby's father, Joshua Anthony Pierce, 22, is scheduled for trial next month on the same charge.

In March, the baby's grandmother noticed something wrong with his leg and insisted he be taken to a doctor. The doctor sent the boy immediately to Children's Hospital in New Orleans, where doctors discovered four broken ribs, a fractured skull and multiple breaks in both of his legs.

The parents gave authorities several explanations -- he was falling off the bed and they grabbed him, for one -- that were inconsistent with his injuries. The fractures were in "several stages of healing," indicating they had been inflicted over time.

Others told police they'd seen Pierce grab the baby when he wouldn't stop crying. Eventually, Polizzi admitted that the boy was once crying, she couldn't get him to stop and shook him out of frustration.

Polizzi was arrested on March 25, while Pierce fled to Jefferson Parish. He was arrested later the same day. Prosecutors alleged that the abuse had been going on since at least early February, when the child was 4 months old.

If convicted at trial of second-degree cruelty to juveniles, which is the abuse of a child that "causes serious bodily injury or neurological impairment," Pierce could be sentenced to up to 40 years at hard labor.

Polizzi, expected to testify against Pierce, told the court Tuesday that she knew he was beating their child, but was too scared of him to intervene.